The transition from non-renewable energies to renewable energies will impact on the taxation of these energies. The use of electric vehicles in the medium term by a larger population will cause a recurring problem of energy theft for the electricity companies. For the user, this will involve the insurance that the data regarding the state of health of the battery, the battery itself, its box and its management system have integrity and have not been tampered with.
An electric vehicle has a battery management system (“BMS”). The function of the BMS is usually to protect the cells of the battery, to control them, to monitor the state of the battery and estimate its state of charge, to maximize its performances as well as to exchange with various components or devices of the system in which it evolves. It thus allows, for example, generating the information required for the display of the state of charge on the dashboard of the electric vehicle.
The BMS manages the discharge, the parameters of the charge and the safe use of the battery by estimating its state through measurement means and algorithms. By controlling its operating range, its environment and by balancing the charge of the battery, the BMS protects the battery and optimizes its performances and durability.
The battery of the vehicle may be used for purposes other than for the operation of the electric vehicle. Indeed, the battery may discharge into an electrical network when its charge is completed but before it is made available to the vehicle. In that case, the mass effect of a large amount of batteries has a stabilizing effect on the electrical network. This configuration is called V2G (“Vehicle to Grid”). There is also the V2H (“Vehicle to Home”) where the battery may provide or receive power from an electrical supply panel of a house, for example during a network power failure. Finally, the battery may discharge into another load (e.g. another battery) connected to the vehicle. It is then V2L (“Vehicle to Load”). The electric vehicle must have a bidirectional charger rather than a unidirectional one in some of these configurations.
The alternating current (AC) charging stations have no integrated charger. This is not the case for direct current quick charging stations that are provided with a charger in order to control the charging voltage and current. This type of station uses a communication protocol for the exchanges with the BMS regarding the parameters of the charging. Some charging stations integrate additional functionalities: energy counter, payment system, internet access depending on whether it is a private or public access charging station. The power consumption required for the charging is available through a communication link with this type of station.
In its tasks, the BMS performs temperature, current and voltage measurements. Furthermore, the BMS keeps the history of these measurements. Depending on the configuration of the battery, these measurements extend to the different cells or cell packs of the battery. The energy available at all times is computed from these measurements and made available to the vehicle management central unit. The BMS may quantify and record the power transactions. The histories are used by the algorithms of the BMS and may also be transmitted outside the BMS.
Although there is a wide variety of BMS, there is an interest in that a BMS be able to indicate a situation of energy theft and substitution of the elements of the battery, box and BMS combination to falsify the pedigree of the system.